---
patternId: media/microphone-process
---

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    <title>How to process audio from the user's microphone</title>
    {# Include the GA object so we can start queuing events. #}
    {% include 'partials/analytics.njk' %}
    <style>
      :root {
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      *,
      *:before,
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    </style>
  </head>
  <body>
    <h1>How to process audio from the user's microphone</h1>
    <button id="startMicrophoneButton">Start using microphone</button>
    <button id="stopMicrophoneButton" disabled>Stop using microphone</button>
    <pre id="logs"></pre>
    {% set script %}
      const startMicrophoneButton = document.querySelector('#startMicrophoneButton');
      const stopMicrophoneButton = document.querySelector('#stopMicrophoneButton');

      let stream;

      startMicrophoneButton.addEventListener("click", async () => {
        // Prompt the user to use their microphone.
        stream = await navigator.mediaDevices.getUserMedia({
          audio: true,
        });
        const context = new AudioContext();
        const source = context.createMediaStreamSource(stream);

        // Load and execute the module script.
        await context.audioWorklet.addModule("processor.js");
        // Create an AudioWorkletNode. The name of the processor is the
        // one passed to registerProcessor() in the module script.
        const processor = new AudioWorkletNode(context, "processor");

        source.connect(processor).connect(context.destination);

        stopMicrophoneButton.disabled = false;
        log("Your microphone audio is being used.");
      });

      stopMicrophoneButton.addEventListener("click", () => {
        // Stop the stream.
        stream.getTracks().forEach(track => track.stop());

        log("Your microphone audio is not used anymore.");
      });

      /* Utils */

      function log(text) {
        document.querySelector('#logs').textContent += `${text}\r\n`;
      }

      window.onunhandledrejection = (event) => {
        log(`> ${event.reason}`);
      };
      window.onerror = (error) => {
        log(`> ${error}`);
      };
    {% endset %}
    <script>{{ script | minifyJs | cspHash | safe }}</script>
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